Slides in this set

Slide 1

Slide 2

X-ray Production1. A cathode is heated so that it releases electrons.2. These electrons are fired across a vacuum by a voltage generated by the mains.3. These electrons hit the negative anode and some of their energy (about 1%) is converted into X-ray photons.4. These X-ray photons can only exit through a window in the casing and there may be sheets of metal either side of the window to absorb X-rays not travelling straight, forming a collimated beam.…read more

Slide 3

X-ray Production· The rest of the energy of the electrons is gained by the anode as heat, so it rotates very fast to get rid of the excess heat.· The energy of one X-ray photon is virtually the same as the kinetic energy of the electrons, as the work function is negligible.…read more

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Slide 5

Slide 6

X-ray absorption ­ the photoelectric effect · Because the energy of X-rays is so high, the work function is considered negligible. · Therefore the photoelectrons produced have virtually the same energy as the X-ray photons that caused them. · This is the main way that low energy X-rays are absorbed.…read more